Water heaters are generally used to provide a supply of heated water. Water heaters can be used in a number of different residential, commercial, and industrial applications. A water heater can supply hot water to a number of different processes. For example, a hot water heater in a residential dwelling can be used for an automatic clothes washer, an automatic dishwasher, one or more showers, and one or more sink faucets. Every storage-type water heater has a limited capacity, and so when one or more processes use heated water at one time, there may be limited or no heated water available from the storage-type water heater until the water heater has sufficient time to heat more water. Some systems use multiple water heaters to provide a supply of heated water.